Fix: const needed for operator* (#17443)

Marlin/src/module/planner.cpp

       const xyze_float_t &max_acc_edit_scaled = max_accel_edit;
     #else
       constexpr xyze_float_t max_accel_edit = DEFAULT_MAX_ACCELERATION;
-      constexpr xyze_float_t max_acc_edit_scaled = max_accel_edit * 2;
+      const xyze_float_t max_acc_edit_scaled = max_accel_edit * 2;
     #endif
     limit_and_warn(targetValue, axis, PSTR("Acceleration"), max_acc_edit_scaled);
   #endif
       const xyze_float_t &max_fr_edit_scaled = max_fr_edit;
     #else
       constexpr xyze_float_t max_fr_edit = DEFAULT_MAX_FEEDRATE;
-      constexpr xyze_float_t max_fr_edit_scaled = max_fr_edit * 2;
+      const xyze_float_t max_fr_edit_scaled = max_fr_edit * 2;
     #endif
     limit_and_warn(targetValue, axis, PSTR("Feedrate"), max_fr_edit_scaled);
   #endif